Tuesday, 5 December 2017

Lizard “Evolves a Complex Trait It Once Lost”?

Image courtesy of Jörg Hempelage, CC BY-SA 3.0 de.

Joel Kontinen

Most female lizards lay eggs, but the Zootoca vivipara (‘live-bearing’) gives birth to young offspring, expect for two subspecies.

This prompted New Scientist to speculate that this is a “rare example of a species re-evolving a complex trait that had been lost.”

According to this scenario, lizards first laid eggs, then stopped laying it, forgetting the trait, and then re-discovered it.

The problem with this kind of reasoning is that any kind of change can be seen as an example of Darwinian evolution, even when it clearly isn’t.

It is an example of Darwinian storytelling, which often tends to be more or less fact-free.


Le Page, Michael. 2017.Lizards re-evolved eggs after thousands of years of live births. New Scientist (5 December).